<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>

    <img src="images/ldh.jpg" alt="">
    <div>时间</div>
    <script>
        var img = document.querySelector('img');
        var div = document.querySelector('div');
        var date = new Date();
        var h = date.getHours();
        if (h < 12) {
            img.src = 'images/zxy.jpg';
            div.innerHTML = ' 亲，上午好、好好写代码哦！';
        } else if (h < 18) {
            img.src = 'images/ldh.jpg';
            div.innerHTML = '亲，下午好、好好写代码哦！';
        } else {
            img.src = 'images/zxy.jpg';
            div.innerHTML = '亲，晚上好、好好写代码哦！';
        }
    </script>
</body>

</html>